Signaling system and apparatus for same



4Nov. 22, 1938. w. A. GRAYE-r AL 2,137,719 V SIGNALING SYSTEM AND APPARATUS Fon SAME Filed July 17, 1936 lllllllllllll INVENTORS.

Weonjray and Lawrence T'oven @Mag/mw Patented Nov. 22, 1938 .UNITED STATES PATENT `OFFICE Weston A. Gray, Cape Elizabeth, and Lawrence T. Stover, Portland, Maine Application July 17, 1936, Serial No. 91,056

2 Claims.

This invention relates, in general terms, to high-way traiiic signaling systems, dealing more particularly with what might be called a radiovisual method of warning the driver of a motor vehicle should a train be in proximity to a railroad crossing over which he is about to pass,

The alarming increase in grade-crossing fatalities, many of which to be sure having been caused by carelessnessof the driver but in many other instances due primarily to improper or inadequate warning devices, has caused inventors to search for a more infallible system than any which at the present time exists.

The conventional types of grade-crossing safety devices, such, for instance, as swinging arms, ringing bells, and even gates, do not fully solve the problem. In a blinding snow storm, a dense fog, together with the natural noises incident to the operating of -the motor vehicle, particularly a closed one-cause the visual signals to be obscured and the audible ones drowned out, thus negativing the dependability of this class of accident-preventing devices.

It is, therefore, withlthe object in view of supplying a more effective and reliable method of warning the vehicle operator when danger lurks at a rail-road crossing which he is about to pass over, and one which will accomplish this object regardless of the elements or the noise in his vehicle, that we have evolved the present system.

In our invention we rely on energy supplied by a radio frequency oscillator set in operation by the train as it enters a prescribed length of trackage adjacent and on each side of the crossing,

' together with antennae or transmission lines of wire placed along each side of the high-way for a predetermined distance from the rail-way tracks.

The vradio waves are picked upby a'tuned circuit within the motor vehicle, this circuit being associated with a lamp, preferably of the neon 'type, the intermittent flashing rays of which project directly into the eyes of the driver and give him a most pronounced warning should the train be within the prescribed area included in the signaling system and his vehicle passing over the high-way within the field of radio activity,-or between the two transmissions lines on each side thereof.

A clearer understanding of the import of ou invention may be gained by reference tothe description found in the following specication when taken in connection with the accompanying drawing disclosing an embodiment which, at the present time, we consider preferable to other possible forms in which the invention might be ,carried out.

device, incorporating therein 'a buzzer, giving an intermittent audible signal.

Referring to the drawing, R represents a railroad track, and H the high-way intersecting the track at the grade-crossing G, C.

At the beginning we will state that various alternative embodiments of the means by which our system is started operating is possible, as for instance, by a mechanically actuated switch element which is directly engaged by the wheels or other parts of the locomotive for closing and then opening the main power line circuit as the train enters and leaves the prescribed zone of action of the system, or-by the use of the well known photoelectric cell associated with the proper devices to set our combination functioning. I But for the purpose of illustratively disclosing the principle upon which our invention is based we have elected to show and describe it in connection and in combination with an insulatedV portion of the trackway, Ra, particularly as in many instances this part of the conventional railway block signaling system may already be installed, and can be utilized; and where no signaling system is in use at a railroad crossing the matter of insulating a proper length of trackage, say for one-half a mile from and on each side of the grade-crossing, is a comparatively simple matter,

Electric power lines P, preferably'althoughnot necessarily of 110 v., make connection with the radio frequency, vacuum tube oscillator I, by means of the relay 2 operated by a battery 3 which is placed in open circuit with the two rails 4, 4 of the insulated portion of the track, terminating at points X, X. When a train enters the insulated track it closes the battery circuit; when it leaves it the circuit is automatically opened. The oscillator starts when the battery circuit is closed, and stops when this circuit is again opened.

On each side of the high-way H is a transmission, or antenna wire 5, to which extend, from the radio frequency oscillator I, the two wires B, 6, respectively.

These transmission wires may be placed on poles at any convenient height from the ground, except that where passing over the track-way they must be elevated sufficiently to allow train clearance. Or the wires may be run under-ground, either for their full lengths or where passing under the tracks.

It will be observed, if reference be had to Fig. 1, that the transmission wires are staggered, that is, while of the same length their ends overlap or terminate in different planes transversely of the high-way, this feature will hereinafter be more fully described.

Within the motor vehicle V is a receiving and indicating device, constituting a tuned circuit. It comprises, as we have illustrated it, a turn of copper tubing 1, the ends of which are connected to an adjustable condenser 8. Associated with this circuit is a lamp, preferably of the neon type, 9.

The foregoing device may be secured to and on the inside of the motor vehicle V in any approved manner, but as shown it is secured in the clamp bracket I and fastened to any convenient portion of the vehicle adjacent the windshield. The copper tube 'I is preferably insulated from the clamp by insulating material Il. A reflector I2 intensifies the light and causes it to be thrown into the drivers face with more brilliancy. As an alternative construction, an electrlc buzzer 9a may be substituted'for the lamp,

this element giving an intermittent audible signal. In operation, the device functions as follows:

'Ihe radio frequency vacuum tube oscillator l is set in operation by closing the 110 v. power.

supply circuit P, through the contacts of the track-operated relay 2, the latter being actuated when a train enters the insulated section Ra of the rail-road R.

Power of suitable frequency is supplied by the oscillator to the transmission lines 5, one of which is placed on each side of the high-way H.

Standing waves of voltage and current, represented by the dot and dash irregular lines S, W, will exist on the two transmission lines, and due to their staggered arrangement the voltage and current waves therein are, respectively, in phase. This produces a eld of uniform intensity between the two lines.

When a vehicle V enters the iield between the two wires 5 the receiving device in the vehicle, embodying a tuned circuit and a neon lamp, actuates in the following manner:

The tuned circuit, the elements composing which are shown in Fig. 2 of the drawing, absorbs energy from the field of radio activity between the two transmission lines through the medium of the "pick up coll 1, (which while susceptible of being constructed in various forms serves the purpose when made as shown in Fig. 2,) in conjunction with the condenser 8 which may be adjusted so as to be resonant to the frequency supplied to the `transmission lines by the oscillator l.

Maximum voltage .will then exist across the coil and condenser to which is connected the neon, or other suitable lamp 9.

Sufficient energy is thus supplied to the lamp to cause it to glow brightly when the vehicle is at a point of maximum current on the transmission lines.

Due to the standing wave phenomena, the lamp will ash on and off as the vehicle moves from a point of maximum current to a point of minimum current. And this process is repeated so long as the vehicle is within the field of the transmission lines, the flash rate being governed by the wave length and the speed of the vehicle.

It is to be understood, of course, that in the described and illustrated method of starting the oscillator into yaction we rely on the wheels and axles of the locomotive or cars of the passing train to close the circuit in which are included the relay 2 and battery 3, serving, in other words as a switch. 'I'he instant the wheels contact the rails 4 in-the insulated portion Ra of the track-way the relay acts to close the main line electric circuit of the power lines P, at Pa, extending to the oscillator l; and until the train has fully cleared the insulated section of trackage, the radio oscillations do not cease.

The same applies to any other specific method of setting the apparatus to work through the immediate presence of the train at either of the points X, X.

We believe that the system herein presented is more reliable than the conventional methods now in vogue at grade crossings in that the signal or Warning is brought more forcibly to, and

into more intimate relation with, the driver of the motor vehicle; and this being the case, the responsibility is wholly his if he fails to act to avoid dangerous consequences.

The receiving set, or the apparatus which is installed within the motor vehicle, is not regenerative, thus will not disturb commercial broadcasting. It may be tuned to any frequency desired but of course must be resonant with the oscillations of the transmission lines and radio frequency oscillator element.

While we prefer two transmission lines, one on each side of the high-way, the system Will operate with but one wire, although at somewhat lessened power.

What we claim is:

1. In a signaling system for high-way vehicles adapted to be installed on a high-way adjacent a.l railway grade-crossing, the combination with a. piece of railway rolling stock, a high-way vehicle, and an electric power line circuit, of a length of railway trackage, including two rails, normally insulated from the main line of trackage and extending for a predetermined distance from, and on each side of, said grade-crossing, a radio frequency oscillator operatively connected to the electric power line circuit, a circuit-opening-and-closing apparatus, including a relay, adapted to close the electric power circuit to said radio frequency oscillator when said rolling stock passes on to the said insulated portion of the trackway, a standing wave transmission line, having wired connection with said radio frequency oscillator, arranged along thc highway for a predetermined .distance from, and on veach side of said grade-crossing, a receiving dcvice installed in said high-way vehicle, tuned in resonance to the frequency of the output of said radio frequency oscillator. and a neon lamp in the circuit of lsaid receiving device in said vehicle adapted, through the instrumentality of the standing Waves from said transmission line,

to produce intermittent flashes of light when the said railway rolling stock has passed on to said insulated portion of trackway, closing the power line circuit to said oscillator, ari said high-way vehicle is moving along said highway within the field of activity of the standing waves from said transmission line.

2. In a signaling system adapted for use at railway-highway grade-crossings the combination with an electric power line circuit,` a piece of railway rolling stock having' wheels thereon operable over the railway, and a motor vehicle adapted to be driven over the high-way, of two rails, forming a part of the railway trackage and normally insulated, electrically, from the main portion thereof, and from each other, a radio frequency oscillator having wire connections with said electric power line circuit, van electric circuit-opening-and-closing apparatus, including a relay, acting normally to open the circuit to said radio frequency oscillator, but adapted to close said circuit upon the said rollingstock passing on to the insulated portion of trackway, a standing wave transmission line, having a wire connection with said radio frequency oscillator, disposed at e'ach side of the highway and extending for a predetermined distance from, and on each side of, saidv grade-crossing, a receiving device in said motor vehicle, tuned in resonance to the frequency of the output from said radio Irequency oscillator, and a lamp associated with said receiving device adapted, through thehinstrumentality of the standing wav'es transmitted from the said transmission lines, to give intermittent iiashes of light when two oppositely-disposed wheels on said railway rolling stock pass on to the insulated portion of trackway and said motor vehicle is simultaneously moving over the highway within the eld of activity of the standing waves from .the two said transmission lines.

WESTON A. GRAY. LAWRENCE STOVER. 

